Urea-Catalyzed N?H Insertion?Arylation Reactions of Nitrodiazoesters

摘要

The power of hydrogen-bond donor catalysis has been harnessed to elicit and control carbene-like reactivity from nitrodiazoesters. Specifically, select ureas have been identified as effective catalysts for N?H insertion and multicomponent coupling reactions of nitrodiazoesters, anilines, and aromatic nucleophiles, thereby preparing a variety of α-aryl glycines in high yield. Experimental and computational studies designed to probe the plausible reaction pathways suggest that difluoroboronate ureas are particularly well-suited to catalyze reactions of nitrodiazoesters with a range of anilines through a polar reaction pathway. Urea-facilitated loss of nitrite followed by addition of a nucleophile conceivably generates the observed aryl glycine products.